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40

The limitation you're hearing has been part of the phone network since long before digital sampling had any part in the telephone system. It is related to the fact that the connection from a land-line phone in your house or office back to the "central office" of the phone company is essentially a continuous connection through a pair of wires. There's ...


24

This is an interesting question. Unfortunately, the answer is probably no for two reasons. There is a nice way of telling how far away a lightning strike was by counting the seconds before the thunder reaches you though. First let me tell you why your method probably won't work, then I'll tell you how to calculate the distance based on the time of arrival ...


23

According to Wikipedia the frequency range of the plain old telephone service is 300Hz to 3.4kHz. So any music you listen to will be missing the low frequencies and missing the high frequencies. If you remember back to the last time you heard hold music on the phone you'll probably remember that it sounded a bit muffled, but I have to say that it's still ...


13

Have a look into the Nyquist theorem. The sampling frequency needs to be at least double the rate of the sampled frequency. I.e. that's why the human ear can hear up to ca. 20kHz and the CD samples at 44.1kHz. Wikipedia Nyquist-Shannon Theorem What do we hear instead if we do listen to (originally) 5 Hz to 20 kHz music through the phone? Is everything ...


13

I think yes, you can get some distance information from analyzing the thunder sound. I am basing this mostly on having personally heard many thunderclaps, both far and near, of reasonably known distance to the lightning. Anyone that has ever experienced a near (100 m or less) thunderclap can tell you it sounds a lot more "sharp" than a distant one, not to ...


7

It can be done, but there's some trade offs. Larger speakers are better at moving longer wavelength (low frequency) waves. When you try to combine a bunch of small surfaces in different locations to recreate a single wave you end up with a some random interference where the wave is stronger or weaker (in 3d-space) (see phased-array antenna for some ...


6

I presume you did not see the flash, so cannot use that as a timing mark. From Wikipedia "The dependence on frequency and pressure are normally insignificant in practical applications. In dry air, the speed of sound increases by about 0.1 m/s as the frequency rises from 10 Hz to 100 Hz. For audible frequencies above 100 Hz it is relatively constant. " You ...


4

This is a neat question. Did you know that adding two Sine waves of the same frequency but different phase together always produces another Sine wave? Of course you can imagine two perfectly out-of-phase Sine waves that "cancel" by adding to a line but in that case you can just imagine the result as a Sine wave with 0 amplitude. Using gnuplot with the ...


4

Taste and smell are mediated by receptors in your body that molecules can attach to. These receptors then give off an electrical signal which is translated in the brain to a certain taste or smell. The details of this are biological and not of importance here. So no, there is no relevant frequency or even wave-like behavior. Touch is a very different thing. ...


4

Actually I have read (although I can't find a reference) that the subjectively perceived psychological notion of pitch itself, although very nearly wholly set by the sound wave's frequencies, is also weakly dependent on the intensity of the sound: that is, a higher intensity sound wave does seem ever so slightly sharper (higher in subjective pitch) than one ...


3

Taste: There are 5 basic tastes that the human tongue can detect. They are sweet, savory, salty, sour and bitter. These are detected by taste receptor cells on our tongue, I won't go deep into the biology part. The basic tastes of sweet, salty and sour have different thresholds, or concentration levels, at which they can be detected. In other words, it is ...


3

The simple way to do this is counting seconds after seeing a lightning flash. The light from the flash travels at $299792458$ meters per second; for all practical purposes one can approximate it as arriving instantaneously at your location from where the lightning strikes. The speed of sound is quite a bit lower, however. It depends on temperature a bit, ...


3

The brain is quite good at filling in for a few missing harmonics. For example music still sounds reasonable on a smartphone speaker even though that speaker is incapable of creating low frequencies. This Wikipedia article explains the phenomenon (thanks to Glen for the link). So it's possible that if you heard the 2nd, 3rd and 4th overtones of 250Hz your ...


3

Well, does playing flute-like across the top of a beer bottle count? Or, better put: a jug-player in a country "Jug band" plays his instrument that way. It's also your call whether blocked instruments with holes along the length qualify, such as an ocarina. I sort of guess what you're looking for is an instrument with an air pocket as the resonance, as ...


3

It isn't possible to create an audio source in mid-air using the method you've described. This is because the two ultrasonic waves would create an audible source if the listener were standing at that spot, but those waves would continue to propagate in the same direction afterwards. You would need, as I point out below, some sort of medium which scattered ...


3

Molecules are broken apart when they collide with one another with enough force to break the bonds that hold them together. These collisions happen all the time and depend on the density of the gas. This is what defines the mean free path. The frequency of collisions increases with density. The force involved in the collisions increases with temperature ...


2

Although your terms are not precise, I have a feeling that what you are describing is a Rubens' Tube. Yes, the combustion reflects the standing wave as shown below (from Wikipedia): Recall that sound is made up of pressure waves and so a standing sound wave means there is larger pressure at some points and lower pressure at others. At the high pressure ...


2

It's certainly possible to produce a sound in the sonic range by intersecting two ultrasonic signals, however, at least as the effect is generally modeled in physics, this interference pattern is only detectable at points where the original waves are intersecting and each of the original waves will continue propagating in its original direction unmodified by ...


2

Hydrodynamic perturbations = change in pressure due to a flow velocity (particles don't return to equilibrium positions). Acoustic perturbations = change in pressure due to the fact the particles undergo an elastic restoring force (for a compressible fluid) which causes perturbations to travel at the speed of sound. Any change in the pressure/velocity ...


2

The surface of the sun is where local plasma cools enough to recombine and go transparent, the photosphere. You would still be deep within the sun's atmosphere, and it would be LOUD. H-bombs are LOUD at the edge of their fireballs.


2

Chris White's answer using an analogy to incoherent light pretty much answers the question; it's fundamentally a question of the statistics of how wave sources add. Here's a slightly different but equivalent rephrasing of Chris White's answer using matrices: Given $N$ wave sources, incoherent waves add "diagonally" ($I\propto N)$, ie, additively. ...


2

Let me give a more detailed back-of-the-envelope approximation, which might actually be able to decide, given the conditions of the problem, if we would be able to hear the sound of Sun. Assumptions: The space between Earth and Sun is filled with uniform air. This is a non-physical assumption. It basically means we are ignoring the gravitational effects ...


2

The Doppler shift for small speeds is $\Delta f/f = \Delta v/c$, where $\Delta v$ is the (signed) speed of the source relative to the detector, and I'm using $c$ as the speed of sound. So let's plug in some numbers. I'm going to use numbers that will produce a large effect to see how larger an effect is plausible. Let's take a woofer operating at $f = 200 ...


1

Based off of that video, the differences you're pointing out are the nice wavefronts from the speaker at 2:04 and then the clap shown at the beginning and the end. It's true that the wave fronts from the speaker (and even the book) give nice "crests" and "troughs" whereas the clap kinda just... is this blob-y thing. There are several potential reasons why ...


1

Sound as you hear it is waves of pressure differences in the air, which is interpreted by your ear as sound. So no, you cannot directly hear electromagnetic radiation (EMR). You could, however, take the EMR and convert it into sound waves in the audible range, which you could listen to. This was done in 1990 for Jupiter by Voyager as it passed Jupiter. It ...


1

It was already mentioned by Carl Witthoft, but I think the ocarina does count, as long as you're not too hung up on the resonance chamber being a tube as such. From Wikipedia: The ocarina, unlike other vessel flutes, has the unusual quality of not relying on the pipe length to produce a particular tone. Instead the tone is dependent on the ratio of the ...


1

You don't explicitly state you are looking for a wind instrument so perhaps a drum would count. Perhaps a snare drum since the snare is on the resonant (non-struck) head or a kettle drum maybe qualifies as a pitched instrument. If you are looking for a wind instrument in particular and Carl Witthoft's suggestions of the ocarina or the jug do not fit the ...


1

That's an interesting link, explaining how if fluid contacts a plate, and if there is a vibration pattern in the plate, what vibration pattern you get in the fluid. As I read it, if the speed of sound in the plate is very high compared to the fluid, the fluid sees a plate that vibrates into and away from the fluid, creating a sound wave that propagates ...


1

At low Renyolds number, the vortex shedding described in the question does not occur, based upon the following simulation videos: http://www.youtube.com/watch?v=ElmTA0t3bEc http://www.youtube.com/watch?v=8o-JC3R9YBY http://www.youtube.com/watch?v=sN9LP5dNWhc However, for higher Renyolds number see Nakamura et al. "Experiments on vortex shedding from flat ...


1

Another thing that happens that can lead you to think that low frequency sounds attenuate quicker is that if you record yourself one time being close to the microphone and another time being farther away, you'll notice that the farther you are the more the lowest frequencies are picked up. This is due to the proximity effect and not to the low frequency ...



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